<?php

defined('ABSPATH') or die("you do not have access to this page!");

if ( ! class_exists( 'rsssl_certificate' ) ) {
    class rsssl_certificate
    {
        private static $_this;

        function __construct()
        {

            if (isset(self::$_this))
                wp_die(sprintf(__('%s is a singleton class and you cannot create a second instance.', 'really-simple-ssl'), get_class($this)));

            self::$_this = $this;

        }

        static function this()
        {
            return self::$_this;
        }

       /**
         *
         * @since 3.0
         *
         * Check if the certificate is valid
         *
         * @return bool
         *
         */

        public function is_valid()
        {
            //Get current domain
            $domain = site_url();
            //Parse to strip off any /subfolder/
            $parse = parse_url($domain);
            if ( !isset($parse['host']) || !function_exists('stream_context_get_params') ) {
				set_transient('rsssl_certinfo', 'no-response', DAY_IN_SECONDS);
            } else {
	            $domain = $parse['host'];
                $certinfo = $this->get_certinfo($domain);

                if ( !$certinfo ) {
                	RSSSL()->really_simple_ssl->trace_log("- SSL certificate not valid");
                	return false;
                }

                //Check if domain is valid
                $domain_valid = $this->is_domain_valid($certinfo, $domain);
                if ( !$domain_valid ) {
	                RSSSL()->really_simple_ssl->trace_log("- Domain on certificate does not match website's domain");
                }
                //Check if date is valid
                $date_valid = $this->is_date_valid($certinfo);
	            if ( !$date_valid ) {
		            RSSSL()->really_simple_ssl->trace_log("- Date on certificate expired or not valid");
	            }
                //Domain and date valid? Return true
                if ( $domain_valid && $date_valid ) {
                    return true;
                }
            }
            return false;
        }

       /**
        *
        * Check common name(s) and alternative name(s) on certificate and match them to the site_url ($domain)
        *
        * @since 3.0
        *
        * @access public
        *
        * @return bool
        *
        */

        public function is_domain_valid($certinfo, $domain)
        {
	        //first check standard situation
	        //Get both the common name(s) and the alternative names from the certificate
	        $certificate_common_names = isset($certinfo['subject']['CN']) ? $certinfo['subject']['CN'] : '';
	        $certificate_alternative_names = isset($certinfo['extensions']['subjectAltName']) ? $certinfo['extensions']['subjectAltName'] : '';
	        //Check if the domain is found in either the certificate common name(s) (CN) or alternative name(s) (AN)
	        $pos_cn = strpos($certificate_common_names, $domain);
	        $pos_an = strpos($certificate_alternative_names, $domain);

	        //If the domain is found, return true
	        if (($pos_cn !== false) || ($pos_an !== false)) {
	        	return true;
	        }

	        //if nothing found, we check for wildcard
	        //strip of asterisk, and check if the wildcard domain is part of current domain
	        $cert_domains = array();
	        if ( $this->is_wildcard() ) {
		        $certificate_alternative_names = explode(', ',$certificate_alternative_names);
		        $cert_domains[] = trim(str_replace('*', '', $certificate_common_names));
		        foreach ($certificate_alternative_names as $subjectAltName) {
			        $cert_domains[] = trim(str_replace('*', '', $subjectAltName));
		        }

		        foreach ($cert_domains as $cert_domain){
			        //If the wildcard domain is found, return true
			        if ( (strpos($domain, $cert_domain ) !== false) ) {
				        return true;
			        }
		        }
	        }

            return false;
        }

	    /**
	     * Check if detection failed
	     * @return bool
	     */
        public function detection_failed(){
	        $certinfo = get_transient('rsssl_certinfo');
	        if ($certinfo && $certinfo === 'no-response' ) {
	        	return true;
	        }

	        return false;
        }

       /**
        *
        * Check if the date is valid by looking at the validFrom and validTo times
        *
        * @since 3.0
        *
        * @access public
        *
        * @return bool
        *
        */

        public function is_date_valid($certinfo)
        {

            //Get the start date and end date from the certificate
            $start_date = isset($certinfo['validFrom_time_t']) ? $certinfo['validFrom_time_t'] : false;
            $end_date = isset($certinfo['validTo_time_t']) ? $certinfo['validTo_time_t'] : false;
            $current_date = time();

            //Check if the current date is between the start date and end date. If so, return true
            if ($current_date > $start_date && ($current_date < $end_date)) {
            	return true;
            }

            return false;
        }

	    /**
	     * Check if the certificate is valid, but about to expire.
	     * @return bool
	     */
        public function about_to_expire(){
	        //if not valid, it's already expired
	        if ( !$this->is_valid() ) {
	        	return true;
	        }

	        //we have now renewed the cert info transient
	        $certinfo = get_transient('rsssl_certinfo');
	        $end_date = isset($certinfo['validTo_time_t']) ? $certinfo['validTo_time_t'] : false;
	        $expiry_days_time = strtotime('+'.rsssl_le_manual_generation_renewal_check.' days');
	        if ( $expiry_days_time < $end_date ) {
		        return false;
	        } else {
		        return true;
	        }
        }

        /**
         *
         * Check if the certificate is a wildcard certificate
         * Function is used in class-multisite.php to determine whether to show a notice for multisite subfolder installations without a wildcard certificate
         *
         * @since 3.0
         *
         * @access public
         *
         * @return bool
         *
         */

        public function is_wildcard()
        {
            $domain = network_site_url();
            $certinfo = $this->get_certinfo($domain);
            //Get the certificate common name
            $certificate_common_name = isset($certinfo['subject']['CN']) ? $certinfo['subject']['CN'] : false;
            $subjectAltNames = isset($certinfo['extensions']['subjectAltName']) ? explode(', ',$certinfo['extensions']['subjectAltName']) : false;

            //Check if the common name(s) contain an *
	        if (strpos($certificate_common_name, '*')) {
		        return true;
	        }

			if (is_array($subjectAltNames)) {
				foreach ($subjectAltNames as $subjectAltName) {
					if ( strpos($subjectAltName, '*') !== false ) {
						return true;
					}
				}
			}
            return false;
        }

        /**
         *
         * Get the certificate info
         *
         * @since 3.0
         * @param string $url
         * @return string|bool
         * @access public
         *
         */

        public function get_certinfo( $url )
        {
            $certinfo = get_transient('rsssl_certinfo' );
            //if the last check resulted in a "no response", we skip this check for a day.
	        if ($certinfo === 'no-response') {
				return false;
	        }

	        if (!$certinfo || RSSSL()->really_simple_ssl->is_settings_page()) {
	            $url = 'https://'.str_replace(array('https://', 'http://'), '', $url);
                $original_parse = parse_url($url, PHP_URL_HOST);
                if ($original_parse) {
                    $get = stream_context_create(array("ssl" => array("capture_peer_cert" => TRUE)));
                    if ( $get ) {
                        set_error_handler(array($this, 'custom_error_handling'));
                        $read = stream_socket_client("ssl://" . $original_parse . ":443", $errno, $errstr, 5, STREAM_CLIENT_CONNECT, $get);
                        restore_error_handler();

	                    if ( !$read ){
		                    $certinfo = 'no-response';
	                    }

                        if ($errno == 0 && $read) {
                            $cert = stream_context_get_params($read);
                            if ( isset($cert['options']['ssl']['peer_certificate']) ) {
	                            $certinfo = openssl_x509_parse($cert['options']['ssl']['peer_certificate']);
                            } else {
	                            $certinfo = 'no-response';
                            }
                        }
                    }
                }
                set_transient('rsssl_certinfo', $certinfo, DAY_IN_SECONDS);
            }
            if ( $certinfo==='not-valid' ) return false;
            if ( !empty($certinfo) ) {
				return $certinfo;
            }

            return false;
        }

	    /**
	     * Catch errors
	     *
	     * @since 3.0
	     *
	     * @access public
	     * @param       $errno
	     * @param       $errstr
	     * @param       $errfile
	     * @param       $errline
	     * @param array $errcontext
	     *
	     * @return bool
	     */

        public function custom_error_handling( $errno, $errstr, $errfile, $errline, $errcontext = array() ) {
            return true;
        }


    //class closure
    }
}